<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<!--节点的优点-->
<div>我是div</div>
<span>我是span</span>
<ul>
    <li>我是li</li>
    <li>我是li</li>
    <li>我是li</li>
    <li>我是li</li>
</ul>
<div class="box">
    <span class="erweima">x</span>
</div>
<script>
    var box = document.querySelector('.box');
    console.dir(box);
</script>
</body>
</html>